UWT Level Switch Ensures Reliable Detection in Chemical Tank Trucks

UWT GmbH has provided a robust sensor solution for aggressive media under challenging tropical operating conditions, ensuring safe and reliable level detection in chemical tank trucks.

A chemical and fuel trading company operating a port storage facility in the Dominican Republic required a dependable system for level limit detection in tank trucks. The goal was to automate the filling process, eliminate manual inspections, and protect personnel from direct contact with highly corrosive sulfuric acid (H₂SO₄).

Requirements and Environmental Conditions

The application presented several significant challenges. In addition to handling strongly corrosive sulfuric acid, the local environment features tropical temperatures around 30 °C (86 °F) and humidity levels of approximately 80 % year-round.

This combination of aggressive chemicals, condensate formation, and high corrosion stress demands a measurement solution that is chemically resistant, climate-proof and low-maintenance. For chemical logistics operators in hot, humid climates, standard sensors often fail to deliver consistent, reliable performance, making specialist technology essential.

Solution: Capacitive Level Limit Switch RFnivo® 8200

To meet these requirements, the company selected the RFnivo® 8200 from UWT GmbH.

The robust rod version features a 250 mm (9.8 in) probe made of stainless steel 1.4404 (316 L) with a PFA coating, providing maximum resistance to sulfuric acid and other corrosive liquids. Depending on the process, high-alloy stainless steels can be used, and FFKM seals are recommended for superior chemical resistance.

The sensor was mounted vertically from the top of the tank trucks to detect the maximum fill level reliably and maintenance-free. During installation, care was taken to minimise direct impacts from filling streams, preventing false switching caused by splashing or surging liquid movement.

Recommended Setup

For reliable detection of H₂SO₄ in chemical tank trucks, the following configuration has proven effective:

• Sensor selection: RFnivo® RF 8200 (capacitive) with Active Shield and Integrated Fail-safe System (IFS)
• Installation: Mounted from the top with a deflector or splash guard to reduce direct liquid impact
• Switching delay: A few seconds to filter out splashing or sloshing during filling
• Sensitivity: Moderate – sulfuric acid has a high dielectric constant, so maximum sensitivity is unnecessary
• Fail-safe mode: FSH for overfill protection / FSL for empty signal
• Maintenance: Regular visual inspection of the probe tip; IFS and Active Shield minimise buildup but do not replace occasional cleaning in heavy aerosol environments

In this application, IFS is primarily used to prevent false switching caused by buildup, condensate, foam or splashing – the typical effects encountered in tropical, acid-laden tank environments.

Technical Features of the RFnivo® 8200

• Wetted materials: Stainless steel 1.4404 (316 L), ceramic, graphite
• Housing: Aluminum, IP68 / Type 4, pressure-tight
• Process temperature: Up to 400 °C (752 °F)
• Ambient temperature: Up to 85 °C (185 °F)
• Operating voltage: 12–250 V AC/DC
• Output options: Relay, transistor, or Profibus PA
• Certifications: ATEX, FM, CSA, INMETRO
• Configuration: Simple via display, DIP switches, or PACTware

Safe and Reliable Operation in Harsh Conditions

The combination of RFnivo® 8200, Active Shield and IFS technology provides a robust, safe solution for level limit detection of sulfuric acid under tropical conditions.

The sensor delivers reliable performance despite heat, humidity and aggressive chemicals. By automating the filling process, it enhances process safety and system availability while protecting personnel, as manual inspection of tank levels is no longer required.

For chemical logistics operations in challenging climates, the RFnivo® 8200 represents a significant contribution to both safety and efficiency.

More information can be found at www.uwtgroup.com